The invention relates to aircraft seats and to the problems encountered by an airline that offers different classes of seating on a single aircraft. As a rule, the total width of a 3-position tourist seat is generally the same as a 2-position first class or business class seat. When there are plenty of extra tourist seats available on a plane, a portion of the center position back cushion can often be folded down, as disclosed in Brennan U.S. Pat. No. 3,877,747 or Marechal U.S. Pat. No. 3,910,632, to a generally horizontal position where it serves as a cocktail table and/or a wide armrest between the end seating positions, permitting the normal center armrests to be folded vertically so as to increase the seat width of the end positions. The extra width increases comfort for the occupant's hip region but does little for the shoulder region since the folded-up armrest is quite hard. Furthermore, the aforementioned seat could probably not be marketed to passengers as a higher class seat since it obviously looks like a tourist seat.
When the demand for seats on a given flight is greater for one class than the seats available, the airline is faced with a number of difficult choices. If they turn the passenger away, they lose revenue, assuming there are unsold seats in another class. If they upgrade a tourist passenger to a higher class, they give more than they bargained for and also run the risk of offending the other passengers in the higher class who paid more for their seats. If there are excess tourist seats and a shortage of higher class seats, there is a risk of losing the potential passenger to another airline, or losing the additional revenue an additional higher class seat would bring. Furthermore, a passenger willing to pay for the comfort of a higher class seat is not pleased when forced to accept a lower class seat.
In an effort to resolve the aforementioned problems of multi-class seating, some airlines have experimented with single class seating. However, the public is usually not very satisfied with such an arrangement, especially when competitors offer multiple classes. A solution to the problem would seem to be a seat which could convert from three positions to two or vice versa.
One company, Flight Equipment Engineering Ltd., of Chesham, England has published literature describing a pair of convertible seats which they refer to as "The Convertible" and the "Series 90 Convertible". In the former design, the center seat back is split vertically down the center so that in a double configuration the center seat back portions can be unlocked and separated from each other and then reattached to the end seat backs. The two unneeded center seat armrests are then pivoted up into a storage recess in the backs of the end seats while a pivoted combination back cushion and wide armrest/cocktail table which ordinarily overlies a portion of the split center seat back is pivoted down to a horizontal use position. Because of the split center seat back, two small tray tables are provided for the center seat back, one for each half. Although the design does indeed convert between 2 and 3 seating positions, it would seem to require a number of additional parts and a not insignificant increase in seat weight because of the double number of supports required to support two center seat back portions and two center seat back tray tables. Additionally, the inboard tray table legs would seem to provide some possibility of interference with the knees of a center position passenger. The need to store the tourist class armrest in the back cushion would possibly seem to present an uneven cushioning effect across the width of the back cushion and would also seem to detract somewhat from the esthetic appearance presented by a more uniform back. The large inboard notches which are present in the seat back cushions in the double seat configuration when the center cushion is moved down to form the armrest might also be considered to be less esthetically pleasing than a seat back having a uniform width and thickness. The "Series 90 Convertible" also has a vertically split center seat back and two center arms. However, the arms do not fold back into the seat backs nor does a portion of the center seat back fold down to form an armrest in the double configuration. Rather, the armrests are lifted completely out of a pair of relatively widely spaced receptacles and are repositioned in a pair of relatively closely positioned receptacles. In the latter position they are covered with a snap-on armcap which forms a wide armrest and cocktail table. Some disadvantages of the latter arrangement are that the separable center armrests could be lost or misplaced while the snap-on armcap is also a loose part which could be lost or broken and which is stored under a seat in the tourist configuration, thus decreasing storage space under one of the seats. Furthermore, loose armrests cannot contain the electrical cables required by inflight entertainment units.
Yet another convertible seat, which has removable center arms and a snap-on armrest cover, is disclosed in materials published by Trans-Australia Airlines. In this arrangement, the center seat back is in three sections which are pivoted near their bottom ends. The center section is the widest and has a single narrow tray table mounted on its rear surface which can be widened after being lowered to its use position by a pair of hinged, foldover side extensions. The conversion operation appears to be fairly time-consuming since the center seat headrest cover must be removed, two zippered cover portions must be opened and closed and several locking levers must be actuated to hold the seat back portions to each other. Finally, the center arms must be lifted out and relocated and the armcap must be moved from its storage position.